When considered superficially, it might appear that the formulation of cleaning compositions of various types would be a matter of routinely selecting various detersive surfactants, detersive bleaches and various detersive adjuncts from the wide variety of such materials known in the art, and combining them to achieve whatever level of cleaning performance is desired. However, on further investigation it is found that this is not the case, especially when superior cleaning is desired. For example, many of the myriad, art-disclosed detersive surfactants are little more than technical curiosities designed for use in specialized operations, and are so expensive that they find no practical use in economical cleaning products of interest to the average consumer for custodial cleaning in the home or business. Various bleaches can be used in cleaning, but may be incompatible with various surfactants. Likewise, detersive adjuncts such as abrasives may be suitable for use on some hard surfaces, but be damaging to other surfaces. Accordingly, the formulator of such compositions is faced with difficult choices when developing superior cleaning products.
The formulation of superior cleaning products for use in kitchens and bathrooms provides special challenges, inasmuch as kitchen soils tend to carry a heavy load of greasy and protein-based materials, and bathroom soils tend to carry a heavy load of "soap scum" materials. Moreover, the environmental surfaces, i.e., fixtures, countertops, sinks, tubs, etc., in kitchens and bathrooms are generally made of highly reflective materials, including various types of tile, glass and chrome-plated metal, on which even minor amounts of soil are highly visible. Accordingly, the consumer expects that modern cleaning products will safely and effectively remove even the final traces of dull, unsightly soils from such surfaces.
Historically, kitchen and bathroom cleaners were highly abrasive powders, perhaps with a bit of added surfactant, and were aptly referred to as "scouring" cleansers. They were harsh, not only on the user's hands, but also on the surfaces to which they were applied. Bleaches were later added to such compositions to break down soils and assist in their removal. While modern abrasive cleansers are formulated to be safer on surfaces and more compatible with skin, such cleansers still rely mainly on the action of the abrasive to remove soil, especially the relatively thick, greasy soap scum soils noted above.
With the advent of liquid cleansers, formulators began using certain solvents to improve cleaning performance. Various alcohols, as well as terpenes present in the well-known lemon oil and pine oil cleansers, were used. While in some instances the amount of such solvents did little more than provide an aesthetic benefit, in others the use of pine oil was at such a level that true solvent cleaning benefits were achieved. In still more modern liquid cleansers, materials such as butyl carbitol are used at solvent/cleaning levels. Apparently, however, many formulators of liquid products were still aware that their products did not perform in optimal fashion. In yet another move to enhance cleaning performance, especially against greasy soils, various suspendable abrasives were added to some liquid cleansers.
While the foregoing would appear to provide a natural progression in the formulation of ever-improving cleaning compositions, the use of abrasives, bleaches and solvents is not without its limitations. Too much abrasive, or too harsh an abrasive, limits a product's usefulness. Too much bleach leads to irritation of the user's hands. Too much solvent can yield noxious odors, skin and eye irritation, and, at the extreme, flammability of the product.
In a manner not unlike that seen with hard surface cleansers, the development of fabric laundering compositions has been a progression of steadily improving technologies, starting with common soaps, through synthetic detergents, built detergents, enzyme detergents, up to and including the most modern detergents with bleaches and bleach activators.
Despite of the wide recognition that various liquid solvents can provide outstanding removal of greasy soils and stains from a wide variety of surfaces, comparatively little attention has been paid to the solvent mode of action for cleaning purposes, outside of dry cleaning operations and, as noted, in certain modern hard surface cleansers. Presumably, that may be due to various formulation and other problems associated with the use of solvents. Some solvents may be toxic, malodorous or flammable at effective usage levels. Liquid compositions containing high levels of solvents and ionic ingredients may be unstable, due to the well-known "salting-out" effect. Still other solvents may be so strong as to dissolve various plastic materials with which they come in contact. In any event, the traditional solvents are all liquids, and are thus unsuitable for formulation into powdered or granular cleaning products.
The cleaning action of bleaches can contribute importantly to the overall effectiveness of hard surface cleaners. Unfortunately, the use of conventional hypochlorite bleaches with conventional solvents can lead to instability of liquid cleaning products.
By the present invention, it has been determined that certain "short-chain" surfactants provide a solvent-like cleaning function. Since these short-chain surfactants are water-soluble solids, they can be formulated in either liquid or solid compositions. These short-chain surfactants have low vapor pressures, and have corresponding low odor qualities. They do not suffer from flammability problems associated with many traditional solvents. The short-chain surfactants can be formulated with hypochlorite bleach to provide a most desirable and effective mixed solvent-bleach cleansing action. When formulated in the manner disclosed herein, these short-chain surfactants provide excellent cleaning against kitchen and bathroom soils. In addition, these short-chain surfactants are low sudsing and may be used in fabric cleaning compositions, including the concentrated laundering processes of U.S. Pat. Nos. 4,489,455 and 4,489,574 or in front-loading "European-style" automatic washing machines where sudsing can be problematic.